4C20.60 - Heat of Crystallization
The heat packs have an activating button. Gently push on the button and the solution of sodium acetate will start to change to a solid. As it does so it releases heat.
- B. Sandnes, "The Physics and the Chemistry of the Heat Pad", AJP, Vol. 76, #6, June 2008, p. 546.
- Narayanan Menon, "A Simple Demonstration of a Metastable State", AJP, Vol. 67, #12, Dec. 1999, p. 1109.
- Sophie Bushwick, "Conquer Cold With DIY Hand Warmers", Popular Science, Vol. 286, #6, Dec. 2014, p. 79.
- Theodore Gray, "Icy Hot", Popular Science, Vol. 279, #5, Oct. 2007, p. 80.
- Cy Tymony, "Cheap Gel Packs for Swollen Muscles", Sneaky Uses for Everyday Things, p. 7.
- "Heat Packs. Item # 3227 Series Suggested Lesson Plans for Elementary, Middle, and High School", American Scientific.
- Borislaw Bilash II, “Heat Me Up With Heat of Crystallization“, A Demo A Day – A Year of Physical Science Demonstrations, p. 63.
- Borislaw Bilash II, “Crystal Heat Pack“, A Demo A Day – A Year of Physical Science Demonstrations, p. 170.
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